I don't think the MAlign has anything like OFS' motives in mind with the current campaign to foment rebellions to blame on Manticore. They have no intention of stepping in to solve any problems, they just want OFS and Frontier Fleet tied up and blaming Manticore for the rebellions.
It makes sense in a way; the Verge is still a resource to be tapped. 'Saving' a situation is one of the easiest ways to conquest *cough* *Sevastapol* *cough*. They're watching the Andermani 'fish in troubled waters'; they may not be as exploitive (at first) as OFS, but it is a fast and easy way to grow the Renaissance Factor with minimum effort. Heck, it's basically what Manticore has in Talbot - new, eager markets and a largely willing and cooperative populace.
Adding in the whole 'improve the population' bit is even easier - just administer your first group of genetic fixes along with the prolong treatments. It's for their own good, after all...
And as to the Detweillers, the plan may not have been quite so heartless to start, but I'm not so sure. Anger, hubris, and intellect make a very dangerous combo. There's a reason for the 'mad scientist' stereotype - I've known a couple. And their desire to punish their detractors/rivals/foes is something to be seen. In one case he stopped seeing anyone against him as being a 'real' human; from there he segued into full-on paranoid psychosis. He's on medication for that, now, thank goodness. Still a brilliant research guy - but I still recall the hundred-and-twenty page write-up he did to plan the demise of his rivals.
Anyhow, just my humble opinion.
Dave